What works for you is the only thing you know or care about. Everyone feels the same way. John Donne was wrong. How?

No way we can exist in the world as "islands" because we need others.  Without others we are nothing.  Even or value to ourselves is based upon the acceptance of others.  We are naturally going to take care of ourselves - that is called looking out for #1.  But in order to do so we have to deal through others.  So the deaths of some people may not affect us as much as of those we are close to but they affect us because we feel for them which is natural sympathy and because we share in their tragedy as human beings it helps to make us more careful about and appreciative of our own lives.  So everything does have an effect on others.  

As a hackneyed philosopher once said ... The main thing that separates Humanity from the rest of the animal kingdom, is our consistent ability to place the wants of the individual above the good of the group.